farms.farms_dni.farms_dni

farms.farms_dni.farms_dni(F0, tau, solar_zenith_angle, De, phase, phase1, phase2, Tddclr, Ftotal, F1)[source]

Fast All-sky Radiation Model for solar applications with direct normal irradiance (FARMS-DNI)

References

Xie, Y., Sengupta, M., Dudhia, J., 2016. A Fast All-sky Radiation Model for Solar applications (FARMS): Algorithm and performance evaluation. Sol. Energy 135, 435-445. Xie, Y., Sengupta, M., Liu, Y., Long, H., Min, Q., Liu, W., Habte, A.,

  1. A physics-based DNI model assessing all-sky circumsolar radiation.

iScience 22, doi.org/10.1016/j.isci.2020.100893. Yang, J., Xie, Y., Sengupta, M., Liu, Y., Long, H., 2022. Parameterization of cloud transmittance for expeditious assessment and forecasting of all-sky DNI. J. Renewable Sustainable Energy 14, 063703.

All arrays should have the same shape (n_times) or (n_times, n_lats, n_lons)

Parameters:

  • F0 (np.ndarray) – extraterrestrial solar radiation (Wm-2).

  • tau (np.ndarray) – Cloud optical thickness (cld_opd_dcomp) (unitless).

  • solar_zenith_angle (np.ndarray) – Solar zenith angle (degrees). Must represent the average value over the integration period (e.g. hourly) under scrutiny.

  • De (np.ndarray) – Effective cloud particle size (diameter, micron).

  • phase (np.ndarray) – Cloud thermodynamic phase (water:1, ice:2)

  • phase1 (np.ndarray) – np.where( phase==1 )

  • phase2 (np.ndarray) – np.where( phase==2 )

  • Tddclr (np.ndarray) – Calculated in REST2. Transmittance of the clear-sky atmosphere for direct incident and direct outgoing fluxes (dd). Tddclr = dni / etdirn

  • Ftotal (np.ndarray) – GHI (Wm-2)

  • F1 (np.ndarray) – First order solar radiation given in FARMS (Wm-2). See Xie et al. (2016) for more details.

Returns:

  • Fd (np.ndarray) – Direct radiation in the downwelling direction (Wm-2). It includes the narrow beam and the scattered radiation in the circumsolar region.

  • dni_farmsdni (np.ndarray) – DNI computed by FARMS-DNI (Wm-2).

  • dni0 (np.ndarray) –

    DNI computed by the Lambert law (Wm-2). It only includes the narrow

    beam in the circumsolar region.